I have a PLCBUS 1141+ PC interface.When I send a command to it, nothing really happens.The LED on the case flickers a bit, makes a bit of a buzzing sound, but no devices pick up the command and turn on or off.No bytes are received by the PC after sending the command. I normally see a message back to the PC after each command.

It seemed to work for about 1 hour and has now stopped working.I left the unit unplugged for about 24 hours, but it still does not work.